1. Field of the Invention
The present invention relates to a three-dimensional processing data setting system for setting three-dimensional data of a processing pattern for a laser marking equipment for processing a three-dimensional work surface with a laser beam, in particular a three-dimensional work surface, such as a laser marking machine for printing a work surface, a method for setting the three-dimensional data, a computer program for setting the three-dimensional data and a recording medium with the three-dimensional data recorded thereon readable by a computer, and a laser marking equipment.
2. Description of Related Art
A laser marking equipment scans a specified scan field of a work such as parts and products with a laser beam so as thereby to perform processing, such as printing and marking, the work surface.
FIG. 1 is a diagram illustrating a laser marking machine. The laser marking machine comprises a scan control processing 1, a laser marking processing 2 and an input processing 3. Excitation light generated by an excitation processing 6 of the scan control processing 1 excites a laser medium 8 of the laser marking processing 2. A laser beam emanating from the laser medium 8 is expanded in diameter by a beam expander 53 and directed toward a scanner processing 9 by a reflection mirror 54. The scanner processing 9 deflects the laser beam L so as to scan a work surface WS, thereby processing, i.e. marking or printing, the work surface WS. page 3 line 3-8 A1
FIG. 2 schematically shows the scanner processing 9. The scanner processing 9 comprises X, Y and Z-axis scanning devices comprising galvanometer mirrors 14a and 14b associated with galvanometer motors 51a and 51b, respectively. The X-axis and the Y-axis scanning device which are arranged so that their optical axes across perpendicularly to each other scan a scan field in X-axis and Y-axis directions, respectively. The laser beam L is focused on the work surface by an fθ lens 15.
Aside from such the laser marking machine capable of scanning a plane scan field, there has been developed a laser marking machine capable of adjusting a focal distance of a laser beam as described in, for example, Unexamined Japanese Patent Publication No. 2000-202655. As shown in FIG. 3, this laser marking machine is adapted to vary a spot size of a laser beam incident upon an object lens system 20 by axially moving an expander lens 28. In other words, laser marking machine is capable of sharply focusing the laser beam on a work surface WS irrespective of a distance of the work W from the laser source 27. A moving distance of the expander lens 28 is determined on the basis of the correlation between a shift distance of a galvanometer scanner 21 and a change in laser beam spot size. Specifically, in FIG. 3, a spot size of the laser beam on the work surface WS is measured when the galvanometer scanner 21 is at a reference position which is farthermost from the laser source 27 and, subsequently, when the galvanometer scanner 21 is moved to a position at any axial distance. As a change in spot size and an axial distance of the galvanometer scanner 21 from the reference position are in proportionality relation, the focal distance of the laser beam varies with a change in the axial distance of the galvanometer scanner 21 from the reference position. Therefore, the laser beam is always focused on the work surface WS irrespective of a distance of the work surface from the galvanometer scanner 21. The laser marking machine equipped with the focal distance adjusting mechanism realizes processing of a work surface in three dimensions, namely X-axis, Y-axis and Z-axis directions.
However, the laser marking machines capable of performing processing in three dimensions requires a user to specify a processing pattern, for example a print pattern comprising a character string, in three dimensions, because works processed by the machine have three-dimensional surfaces. Conventionally, when specifying a work pattern in three dimensions for an NC machine tool capable of performing three-dimensional machine work, a user is essentially required to specify a machine work pattern on the basis of two-dimensional engineering drawings of a work model and a machine work pattern by hand. In order to prepare control data of three-dimensional machine work accurately and effectively by hand, the user is required to have a lot of skill. The hand preparation of control data has a definite ceiling to time saving. In consequence, the laser marking machine is hard to adapt itself to multiproduct early delivery products and multi development and trial production due to a lack of human resources and working hours.
Contrary to this, there is a method using an application program for data preparation that is adapted to automatically generate control data for beam position, a work position and a work angle on the basis of a three-dimensional work model prepared by a CAD system. However, this method encounters various problems for data input such as diverse items to be specified by a user, a demand for specialized parameters and, in consequence, is hard to make data setting easy. In particular, since data of a three-dimensional work surface should be provided by a dedicated 3D-CAD system, it is hard to specify a three-dimensional work surface by the use of other application software. Furthermore, because a three-dimensional work surface and a three-dimensional shape of a processing pattern are different, they must be specified separately. That is, it is necessary to generate data for three-dimensional processing by reading in data of a three-dimensional work surface and data of a three-dimensional processing pattern from a 3D-CAD system, separately. However, since it is too troublesome for a user, in particular for an unaccustomed user, to input data of a processing pattern in consideration of three-dimensional shape.
The laser marking machine, specifically a laser marking machine, is also required to be capable of printing not only in already existing fonts but also in user-installed fonts. The already existing fonts are used for preventing the possibility of variations in print quality in accordance with character compositions resulting from different writing orders and turgidity at joints and intersecting points between lines and loops forming the respective characters. However, in the case of printing characters in three dimensions, since a character itself is printed in three dimensions, a printing surface of the character does not always reflect the font face. In consequence, dedicated processing data peculiar to printing patterns, namely character strings, should be provided by printing location. Even in the case, for example, a character string is pasted to a work surface by the use of a function of a 3D-CAD system and data of the pasted character string is downloaded to the laser marking machine, data of various different character strings are required in accordance with printing locations of the work surface, so that a flood of data is required to be prepared. In particular, when character strings include different characters giving a date at the same positions, the number of data sets is equal to the number of printing locations times the number of printing patterns by work surface. It is quite hard for a user and impractical to generate such a huge number of data sets.